Recent test of SLB SR with an 8ohm 100w dummy load, powered with one secondary from an Antek AS-3222. Produces 25.5v at 3.2A with under 1mV rms ripple. Setup shown has 2SA1943 on an external heatsink and flying lead via Molex and silicone RC car wire. Noise on red scale is RF noise pickup as can be seen in second scope shop with everything powered off. I am using a small ferrite core inductor to remove some of the RF noise pickup at the probe-tip.
Setup:
Ripple in (yellow) and Ripple out (red):
Result shows 120mVrms ripple in and 0.72mVrms ripple out or -44dB reduction. I think it may actually be better but obscurred by the RF noise hash.
RF noise pickup when powered off:
I don't know how Vunce gets his scope probe to be so noise free?
Setup:
Ripple in (yellow) and Ripple out (red):
Result shows 120mVrms ripple in and 0.72mVrms ripple out or -44dB reduction. I think it may actually be better but obscurred by the RF noise hash.
RF noise pickup when powered off:
I don't know how Vunce gets his scope probe to be so noise free?
Attachments
The orders are going out tomorrow - and yes, will include the SLB SR v2 with correction on orientation of Q5.
ut note that SLB SR works fine with a small flag heatsink as I have shown above. It's not even warm and I think a heatsink could be skipped altogether. I recall the predicted dissipation was 250mW at 5A. Easiest thing to do is not even use a heatsink on the older v1 boards.
ut note that SLB SR works fine with a small flag heatsink as I have shown above. It's not even warm and I think a heatsink could be skipped altogether. I recall the predicted dissipation was 250mW at 5A. Easiest thing to do is not even use a heatsink on the older v1 boards.
Hi Spica,
Just place the order on Etsy and make a note what your DIYA handle is. That’s it.
BOM and schematics linked in post 1. But here is is for your convenience.
The SLB (Smooth Like Butter) Active Rect/CRC/Cap Mx Class A Power Supply GB
A single SLB dual rail is the perfect PSU for all 25w Class A amps such as M2/M2X, F4, F5, F6 etc. Fir higher power amps circa 50w with bias currents exceeding 2.5A per channel an SLB is recommend per channel.
Just place the order on Etsy and make a note what your DIYA handle is. That’s it.
BOM and schematics linked in post 1. But here is is for your convenience.
The SLB (Smooth Like Butter) Active Rect/CRC/Cap Mx Class A Power Supply GB
A single SLB dual rail is the perfect PSU for all 25w Class A amps such as M2/M2X, F4, F5, F6 etc. Fir higher power amps circa 50w with bias currents exceeding 2.5A per channel an SLB is recommend per channel.
It’s really designed for steady large Class A currents up to 5A - more can be attained with some changes to CRC.
As it is, it can provide 5A steady forever. Peak will depend on output impedance of BJT and supply in 15,000uF bulk cap (which is bigger than most caps used on a Class AB CRC). If I recall, the simulation showed a max ripple current about double the steady state current. Without another simulation and analysis, I would estimate that it can provide up to circa 10A (double rated) for 1 half cycle of 120Hz or 240Hz or circa 250 microseconds. Hugh or Jan might be able to give a more accurate answer with a simulation.
As it is, it can provide 5A steady forever. Peak will depend on output impedance of BJT and supply in 15,000uF bulk cap (which is bigger than most caps used on a Class AB CRC). If I recall, the simulation showed a max ripple current about double the steady state current. Without another simulation and analysis, I would estimate that it can provide up to circa 10A (double rated) for 1 half cycle of 120Hz or 240Hz or circa 250 microseconds. Hugh or Jan might be able to give a more accurate answer with a simulation.
No worries - the links are not highlighted well enough. I should change the color to bright blue or green to make it easier to see.
I have been listening to my M2X more and more powered by this PSU and have to say, it sounds great. I have never been happy with any (and believe me I fired many) of the previous power supply designs for the M2 - they all had hum and ground loop issues of some sort. The amp is silent now finally.
I have been listening to my M2X more and more powered by this PSU and have to say, it sounds great. I have never been happy with any (and believe me I fired many) of the previous power supply designs for the M2 - they all had hum and ground loop issues of some sort. The amp is silent now finally.
Hi X and experienced DIYers,
I'm picking up problems soldering onto the earth lands on this board. I have a Weller PU 81 station with a WSP 80 iron, and a range of tips. I'm currently using the 5 mm chisel to get the solder to take on the lands, but am not certain what the correct temperature setting should be. Your advice will be highly appreciated. The solder is a 0.7 mm 2% flux SAC305 and lead free wire.
Thanks,
Kevin
I'm picking up problems soldering onto the earth lands on this board. I have a Weller PU 81 station with a WSP 80 iron, and a range of tips. I'm currently using the 5 mm chisel to get the solder to take on the lands, but am not certain what the correct temperature setting should be. Your advice will be highly appreciated. The solder is a 0.7 mm 2% flux SAC305 and lead free wire.
Thanks,
Kevin
Last edited:
